Why are Pant, Gill, and Parag not part of England T20I series?

Rishabh Pant and Shubman Gill, who featured in India's squad for the recently-concluded Border-Gavaskar Trophy, have been excluded from the upcoming T20I series against England. Reports suggest that both players have been rested in view of the crucial ODI series that follows. Meanwhile, Riyan Parag, who had a promising start to his international career, remains unavailable due to injury.